Reactivation of Epstein-Barr virus in Sjögren's syndrome.

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and destruction of salivary and lacrimal glands. This condition may be limited to glandular tissues or may be associated with other autoimmune disorders such as rheumatoid arthritis or systemic lupus erythematosus. Since the environmental factors that initiate SS are unknown, we have investigated the potential role of Epstein-Barr virus (EBV), cytomegalovirus (CMV) and other viruses. We observed that epithelial cells in salivary gland biopsies of SS patients contained antigens reactive with monoclonal antibodies against EBV-associated antigens. These antigens were not found in other tissues of SS patients and were absent in salivary gland biopsies from normals and patients with other autoimmune diseases lacking SS. Also, the content of EBV DNA in the saliva of SS patients was significantly greater than in age- and sex-matched controls or individuals with other autoimmune disorders. These studies provide one of the first examples where a specific viral agent may be implicated in perpetuating a chronic autoimmune disease. However, great caution must be used before an etiologic role can be attributed to an ubiquitous agent such as EBV.